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authorLinus Torvalds <torvalds@linux-foundation.org>2013-09-12 06:09:14 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-12 06:09:14 +0400
commitb3b7568490bb66688ee64f4ab72ec697f4f983c5 (patch)
treee55098d4c05d2169e1934dcdf816e476c2af86f8 /drivers
parentc2d95729e3094ecdd8c54e856bbe971adbbd7f48 (diff)
parent19e8697ba45e7bcdb04f2adf6110fbf4882863e5 (diff)
downloadlinux-b3b7568490bb66688ee64f4ab72ec697f4f983c5.tar.xz
Merge tag 'for-3.12' of git://git.linaro.org/people/sumitsemwal/linux-dma-buf
Pull dma-buf updates from Sumit Semwal: "Yet another small one - dma-buf framework now supports size discovery of the buffer via llseek" * tag 'for-3.12' of git://git.linaro.org/people/sumitsemwal/linux-dma-buf: dma-buf: Expose buffer size to userspace (v2) dma-buf: Check return value of anon_inode_getfile
Diffstat (limited to 'drivers')
-rw-r--r--drivers/base/dma-buf.c32
1 files changed, 32 insertions, 0 deletions
diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c
index 1219ab7c3107..1e16cbd61da2 100644
--- a/drivers/base/dma-buf.c
+++ b/drivers/base/dma-buf.c
@@ -77,9 +77,36 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
return dmabuf->ops->mmap(dmabuf, vma);
}
+static loff_t dma_buf_llseek(struct file *file, loff_t offset, int whence)
+{
+ struct dma_buf *dmabuf;
+ loff_t base;
+
+ if (!is_dma_buf_file(file))
+ return -EBADF;
+
+ dmabuf = file->private_data;
+
+ /* only support discovering the end of the buffer,
+ but also allow SEEK_SET to maintain the idiomatic
+ SEEK_END(0), SEEK_CUR(0) pattern */
+ if (whence == SEEK_END)
+ base = dmabuf->size;
+ else if (whence == SEEK_SET)
+ base = 0;
+ else
+ return -EINVAL;
+
+ if (offset != 0)
+ return -EINVAL;
+
+ return base + offset;
+}
+
static const struct file_operations dma_buf_fops = {
.release = dma_buf_release,
.mmap = dma_buf_mmap_internal,
+ .llseek = dma_buf_llseek,
};
/*
@@ -133,7 +160,12 @@ struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
dmabuf->exp_name = exp_name;
file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, flags);
+ if (IS_ERR(file)) {
+ kfree(dmabuf);
+ return ERR_CAST(file);
+ }
+ file->f_mode |= FMODE_LSEEK;
dmabuf->file = file;
mutex_init(&dmabuf->lock);